Material for road surfaces and method of applying same



Patented Feb. 25, 1930 UNITED STATES PATENT OFFICE JAMES FREDERICK BENNETT, OF DBONFIELD, AND JOHN HADFIELD, OF SHEFFIELD,

' ENGLAND MATERIAL FOR ROAD SURFACES AND METHOD OF APPLYING SAME No Drawing. Application filed May 31, 1927, Serial No. 195,580, and in Great Britain .Tune 4, 1926.

dients such as tar or resin to vary the nature of the product, or such as limestone, saw-dust or other forms of cellulose to act as fillers to increase its strength and bulk, the object of the invention being to provide means for enabling such materials to be used for surfacing roads and the like.

When certain organic oils derived from vegetable, animal or fish sources and sulphur, or resin and sulphur, or bitumen and sulphur are heated to a temperature in the neighbourhood of 300 F. a vulcanizing chemical reaction takes place with evolution of gas and it has been proposed to use the resultant product for various purposes. According to the present invention, however, a road, path,

playing, floor covering or like surface is produced by heating castor or other organic vulcanizable oil, bitumen and sulphur in the proportion of thirty two parts of oil and bitumen with thirteen to sixty four parts of sulphur (with or without tar, and resin and filling and colouring matter or any of them) until evolution of gas takes place, spreading the mass obtained on a suitable foundation 7 and rolling or otherwise pressing it whilst still hot. Y a

In a modification the mass obtained on evolution of gas may be cooled and subsequently re-heated and spread on the foundation after which it is rolled or otherwise pressed whilst still hot to form the required surface.

For renewing or repairing a road, path, playing or like surface the product may be dissolved or fiuxed in creosote, tar or other solvent and then sprayed or painted on'the surface by any suitable means.

In carrying out the invention castor oil is preferably used although any other vulcanizable organic oil such as linseed oil, cotton seed oil, or oil derived from other vegetable or from animal sources may be used. The oil is mixed with bitumen such as that obtained from the distillation of petroleum, or Trinidad Lake bitumen, Stockholm tar and bitumens of a like nature, the preferred amount being half the weight of oil, though the bitumen may range from a small proportion up to slag or the like, to harden the product or saw-.

dust, paper, or fibrous matter such as cocoanut fibre, felt or hair to give strength to the material. The heat is maintained until the ingredients assume a plastic or semi-fluid state at a temperature of about 250 .F. the time of heating increasing with the amount of bitumen added. The temperature is now,

raised still further to from 280 F. to 850 F., when the material becomes more fluid. This higher temperature is maintained for a certain time until gas is evolved, the time depending upon the proportion of sulphur which has been added, the greater the amount of sulphur, the shorter the time. With the evolution of gas the liquid changes to a spongy mass and it is then immediately removed from the vessel, spread on the previously prepared road foundation and rolled thereon, whereby it is simultaneously pressed and cooled. The rollers employed may be faced to apply any desired pattern to the surface. In some cases the rolling may be replaced by other means for pressing by the employment of suitable tools.

In this manner a road may be provided with a silent, vibration-damping,hard-wear ing surface capable oftaking all kinds of tralfic which its foundation is designed to cope with and eminently suitable either for general use, as in the business thoroughfares of cities and towns, or for particular use outside hospitals and places of worship.

If delay occurs in removing the spongy mass and the chemical re-action is permitted toicontinue the product'is charred and ruined. It is therefore important to remove the spongy mass from the heating vessel and to put in hand the combined pressing andcooling operation to stopthe chemical re-action at an early stage after formation of the spongy mass and the first evolution of gas and before the chemical reaction has proceeded far enough to damage the product.

The proportion of sulphur may be considerably increased up to about twice the weight of oil. The efiect of increasing the sulphur content is to add to the hardness of the procluct. The consistency of the spongy mass produced on the evolution of gas is also dependent on the sulphur content, the less sulphur the greater the fluidity of the mass.

If desired a small proportion of parafin wax, tar, resin or the like may be added, the effect being to soften the product and to increase its adhesive properties.

If desired the product obtained on the evolution of maybe removed from the heating vessel, cooled in sui able moulds and subsequently be re-melted and moulded or spread into the desired shape or position without impairing its properties. This modification may be usefully employed for surfacing or repairing a road or the like by less skilled labour than that required for preparing and laying the product in situ. The previously prepared product is simply re-melted and applied after which it is pressed or rolled in order to concentrate the material and to give the desired finish to the surface.

The rubber-like material obtained by'the employment of the present invention may be used for other like surfaces and may be modified in accordance therewith. For example, when it forms the playing surface of tennis courts a green or other coloured powder may be incorporated with the other ingredients before or during the heating process. Or it may be laid on the surfaceand rolled into the material during the simultaneous pressing and cooling operation.

When the material is used as a floor covering the simultaneous pressing and cooling may be' effected after the spongy mass has been spread on a suitable fabric foundation of canvas, string or the like.

The rubber-like material obtained during the employment of the present invention when made without an excess of other insoluble ingredients dissolves or is'fiuxed in the usual rubber solvents such as benzol, carbon bi sulphide, creosote, tar and the like. When so dissolved, or fluxed'it may be used for renewing or repairing a road, path, playing or like surface by. spraying or painting the solution thereon.

1 What we claim is 1. The method ofproclucing a wear resisting surface which comprises heating an organic vulcanizable oil, bitumen and sulphur in the'proportion of thirty two parts of oil and bitumen with thirteen to sixty four parts of sulphur until evolution of gas takes place, adding tar or resin, and immediately spreadingthe mass obtained on a suitable foundation before it is charred and rolling or otherwise pressing it whilst still hot to cool the same, substantially as and for the purpose specified.

2. The method of producing a wear resisting surface which comprises heating an organic vulcanizable oil, bitumen and sulphur in the proportion of thirty two parts of oil and oitumen with thirteen to sixty four parts of sulphur until evolution of takes place, cooling the mass before it is charred, re-heating it, spreadii'ig it on a suitable foundation and rolling or otherwise pressing it whilst still hot, substantially as and for the purpose specified.

a. The method of making a surfacing material which comprises heating an organicvulcanizable oil, bitumen and sulphur in the proportion of 32 parts of oil and bitumen with 13 to 6% parts of sulphur until evolution of gas takes place and cooling the mass before it 's charred, substantially as specified.

The method of making a surfacing mawhich comprises heating an organic vulcanizable oil, bitumen and sulphur and, when gas is evolved, immediately cooling the sane to prevent furt or chemical reaction.

5. The method of making a surfacing maerial which comprises heating an organic *ulcanizable oil, bitumen and sulphur tosether with a filler to a temperature higher ran 250 F, maintaining the mixture at a iio'h temperature until gas is evolved, and

u ll.

.nmcuiately cooling the same to prevent fur- Lcr chemical reactlon.

In testimony whereof we hereunto afiiX our signatures.

JAMES F. BENNETT. JQHN HADFIELD. 

